1. Field of Invention
This invention relates to custom dental trays, specifically to custom dental trays that indicate pressure from occlusal contact.
2. Occlusal Treatment
Splints, stents, and night guards are types of dental appliances which have been fitted with sensors to indicate pressure from occlusal contact. Generally, such appliances are fairly costly and time consuming to fabricate, and are made by a dental laboratory. They are useful for collecting data on dental occlusion, jaw muscle activity during sleep, and so on. Such appliances are primarily used to diagnose or treat patients exhibiting high levels of activity in the muscles of mastication during various stages of sleep, known as bruxism, or mandibular parafunction. Patients generally take such appliances to their homes, and wear them in the mouth during sleep, typically accompanied by one or more data collection or analysis devices. Generally, patients who receive treatment with these appliances are symptomatic, and are well aware that they have an advanced problem that needs treatment.
In contrast, there is a large group of people who are unaware that they have a problem that needs treatment. Many people exhibit moderate levels of parafunction, but do not have sufficient symptoms to cause them to believe they need treatment. They are predominantly unaware that they are slowly chipping or wearing away their teeth, slowly spreading fractures through their teeth, weakening exisiting dental restorations, traumatizing the alveolar bone around the teeth, traumatizing their temporomandibular joints, or causing pain in the head or neck. They tend to become aware of these problems only when they have unnecessarily progressed to obvious symptoms, have lost function or structure, and need more costly treatment.
Sleep research shows that approximately one third of the general population could benefit from use of a simple hard night guard. Generally, hard night guards are made by a dental laboratory, are time consuming to fabricate, require multiple office visits to fit, and are somewhat costly for patients. Therefore, patients must somehow become aware that they could benefit from the use of a night guard before they will want to proceed with night guard fabrication.
Dental practitioners are able to rapidly assess signs of parafunction, such as linea alba, serrated tongue, TMJ irregularities, dental attrition, vertical bone loss, and so on. However, even if time is taken to show patients these signs, they remain relatively meaningless to them. A practitioner can spend significant time describing the sequelae of these problems to patients, but patients are generally not motivated to treat problems that they see little or no direct evidence of. Dental practitioners therefore have the undesirable task of being obligated to inform patients that they need a somewhat costly night guard to prevent a problem the patient is not sure they have. Therefore, dental practitioners need of a rapid, low cost means to help patients realize that significant parafunction is indeed occurring.
In addition, indicators of occlusion are useful in the practice of dentistry for a variety of other purposes, including occlusal studies, occlusal records, prosthetic fitting, and so on.
3. Description of Prior Art
Custom trays are trays which are designed to custom fit over at least a portion of a person's teeth. Custom trays generally fit with a greater accuracy of adaptation to the shapes of the teeth than stock trays. Custom trays are used in dentistry for performing various functions in the mouth. These functions include impression material carrier, bruxism protection, athletic guard, airway maintenance, surgical stents, medicament carrier, and so on. Medicaments to be carried in custom trays include tooth whitening agents, anticariogenic agents, antibacterial agents, desensitizing agents, and so on. In contrast to the laboratory fabricated splints, stents and night guards with occlusal pressure indicators, custom trays are commonly made in dental offices.
In one common process for forming custom dental trays, the steps include taking impressions of the teeth, pouring plaster into the impressions to form plaster models of the teeth, providing a manufactured square-cut or round-cut thin sheet of a custom tray sheet having a specified uniform thickness, heating said sheet until it is moldable, applying a specialized vacuum source to the moldable sheet to mold it to fit the shapes of the teeth on the plaster model, allowing the moldable sheet to cool until it becomes a non-moldable sheet, and trimming the non-moldable sheet to form a dental tray. Trays formed with this process tend to be accurately conformed to the teeth, have good retention to the teeth, and have a low rate of fluid leakage.
Due to the moderate cost of the specialized vacuum source used in the above process, and the skill of the personnel required, this method of forming custom trays is performed in dental offices or dental laboratories. In addition, while forming custom trays using this process can be accomplished in a single patient visit, it is much more common for an additional patient visit to be made to deliver the completed trays, due to the amount of time required to complete the trays.
In a second process for forming custom dental trays, a low melting point polymer tray material is heated until moldable, and then molded intraorally to conform it to fit the shapes of the teeth. The process for molding the tray material intraorally include instructing the patient to bite down lightly, push the tongue against the roof of the mouth, suck air and water out of their mouth, conform the tray material to the shapes of the teeth with fingers, then remove and hold under cold water. The custom tray material and process is intended to reduce the time required to form a custom dental tray. It is also intended to permit the formation of a custom dental tray without the need for costly specialized vacuum equipment, or skilled dental office personnel. Such custom dental trays could be constructed rapidly by dental office personnel, or could be constructed by unskilled persons at home. However, trays made with this process tend to be less accurately conformed to the teeth.
In a third process for forming custom dental trays, there is provided a thin pliable inner sheet of tray material nested in an outer thicker dental tray. The pliable inner tray is pre-loaded with a medicament, such as a sticky whitening gel. The thicker tray is used to seat the pliable inner tray on the dental arch, and is then discarded. The pliable inner tray is adhered to the teeth via the sticky medicament, and is finger-molded to enhance adaptation to the teeth. The moldability of the pliable inner tray material is not substantially altered during this process. Trays made with this process tend to be less accurately conformed to the teeth.
In a fourth process for forming custom dental trays, a pliable tray is pre-loaded with a sticky medicament. The pliable tray is adhered to the teeth via the sticky medicament, and is finger molded to enhance adaptation to the teeth. The moldability of the pliable tray material is not substantially altered during this process. Trays made with this process tend to be less accurately conformed to the teeth.
In a fifth process for forming custom dental trays, a dental impression is made of the teeth. The teeth are forcefully pushed into the cured impression imprint with a sheet of moldable tray material interposed, thereby molding the tray material to the shapes of the teeth to the form a custom tray. Trays made with this process tend to be conformed to the teeth with moderate accuracy.
In a sixth process for forming custom dental trays, an imprint is made of the teeth in a dense putty. The teeth are forcefully pushed into the uncured imprint with a sheet of moldable tray material interposed, thereby molding the tray material to the shapes of the teeth to the form a custom tray. Trays made with this process tend to be conformed to the teeth with moderate accuracy.
The above processes for forming custom dental trays suffer from a number of disadvantages:
(a) Accurately adapted trays require skilled personnel
(b) Accurately adapted trays require costly specialized equipment
(c) Accurately adapted trays can require substantial time
(d) Trays formed are not capable of indicating occlusal pressure
(e) Trays formed intraorally tend to have moderate to poor adaptation to the teeth
(f) Trays formed intraorally tend to have moderate to poor retention to the teeth
(g) Trays formed intraorally tend to have substantial fluid leakage
A tray material and process similar to my custom dental tray material and process would not have been as practical prior to the development of low melting polymers, or other materials which are moldable at temperatures which are tolerated intraorally, and then can be caused to become substantially non-moldable.